According to the docs if security is configured I would need to authenticate. But after looking at mongodb.org/display/DOCS/Security+and+Authentication it seems clear to me I'm not using any authentication. I don't run the process with the --auth option, nor are there any users when I run a db.system.users.find() command.

In the meantime, there are two work-arounds:
1) Enter the credentials for authentication in the browser pop-up window
2) Remove all user credentials from each of your DBs (including admin) using db.system.users.remove()

Greetings Brain,
i am using mongo V 2.4.6 and its on default port 27017, its http console is enabled by default but when you try to access from Network it ask for password and i dont know why as i am new to this and dont know the exact reason. by i have a way to access it.

Create a tunnel to your mongo Server and when you access, it wont ask for password. and if you are using putty.